An indole–rhodamine-based ratiometric fluorescent probe for Pd2+ determination and cell imaging

A ratiometric fluorescent probe for Pd2+ has been constructed through appending indole to rhodamine B. The response process of Pd2+ to probe was also verified by UV-vis, fluorescence, ESI-MS, 1H NMR and density functional theory calculation. Moreover, the highly sensitive and selective probe was successfully applied to monitor Pd2+ in living cells.